This invention relates to a method of receiving a video signal especially a narrow band video signal transmitted through a narrow band transmission line such as a telephone line, a sound tape recorder or the like.
In transmitting or recording-reproducing a so-called wide band video signal of a standard broadcasting system through the use of a narrow band transmission line such as a telephone line, a sound type recorder or the like, it is a practice to store the video signal temporarily in a clock controlled memory and to read out the stored video signal at a selected reading-out speed i.e., at a selected frequency of the reading-out clock signals in order that the stored video signal is converted into a video signal of a given allocation band. For storing the wide band video signal, the memory is required to have a capacity or a number of cells sufficient to store allotted picture elements composing the video signal. Considering the storage of a video signal of a 4.5 MHz bandwidth, for instance, the maximum number of picture elements is 4.5 MHz.times.2=9 M dots/sec and hence the number of cells amounts to (9 M dots/sec.times.1/30 sec)/frame=300 K dots/frame. If these picture elements are transmitted through a transmission line having a 3 KHz transmission bandwidth, it takes, for one frame, (4.5 MHz/3 KHz.times.1/30 sec)/frame.apprxeq.50 sec/frame.